There is an increased interest in preserving fruits and vegetables by drying. Redbeet is generally processed before consumption which influences the stability of betalains in turn which affects the acceptability and health properties. Red beet has high concentration betalains that are used as food colorants and food additives due to their health promoting properties.
The red beetroot raw materials were purchased from the food market (local farmers from Cluj-Napoca) and the reagents from Sigma Aldrich or Merck (Darmstadt, Germany). After preliminary cleaning, peeling and slicing, red beetroot were dehydrated at diferent temperature 55°C, 65°C, 70 °C for 6 hours in a Hot Air Dryer Machine. Total phenolics content was assesed by Folin-Ciocalteu spectrophotometric method using a UV-VIS, JASCO V530 spectro photometer (International Co.,Ltd.,Japan). The radical scaveging activity (RSA%) was assesed by DPPH spectophotometric methods. In parallel, a marketing study was conducted to highlight consumer preference for this type of product that is recommended to consume in the form of snack.
The highest content of total polyphenols was recorded for red beetroot dehydrated at 70 °C with 172.67 (mg. GAE / 100g sample) followed by the sample dehydrated at 65 °C with 140.23 (mg. GAE / 100g sample) and the lowest value recorded for sample dehydrated at 55 °C with 104.96. Regarding the antioxidant activity, the scavenging efficiency of red beetroot dehydrated against the DPPH radical was the strongest due to their high polyphenol content: 47.31 (% RSA) at 70 °C followed by the sample dehydrated at 65 °C with 45.70 (% RSA) and the lowest value recorded for sample dehydrated at 55 °C with 39.29 (% RSA).
Afore mentioned studies indicate that the processing of red beet has influence on betalains and antioxidant activity.